Zoology - Principles of Inheritance and Variation Question with Solution | TestHub

The chromosomal disorder occurs when there is addition or deletion of chromosome in the individual. In case of trisomy of the${21}^{\mathrm{s}\mathrm{t}}$chromosome causes Down's syndrome. The affected individual is short-statured with small round head, furrowed tongue and partially open mouth. Palm is broad with characteristic palm crease. Physical, psychomotor and mental development is retarded.